Ok guy I have an 06 2.4 cobalt ss 5 speed and was being hard on it yesterday, while shifting into 2nd it ground the teeth, now won't go into 2nd and whines in 3rd and 4th, any suggestions? Or time for a new trans?

 

Sounds like you killed your gears

I wouldn't say new transmission cheapest route is probably a used transmission swap that you know is in working condition

 

As cheap as you can pick up a used f23, it's not even worth trying to fix yours. Search junkyards for low mileage transmission. Any year manual transmission cobalt with a 2.2 or a 2.4 will work for you. The XFE cobalts have a higher final drive gear so you may want to avoid those but other than that, they're all the same. And you can pick one up easily for a few hundred bucks